Build Up

Second Story Addition Cost Calculator

Estimate the cost to build up, including structural reinforcement, bedrooms, bathrooms and finish level, adjusted for your region. Free and instant.

Estimate the cost
Under a minute Structural options Region adjusted
Scope Step 1 of 4

What Is the Scope?

How much of a second story are you adding?

Estimates include typical materials and labor. Permits, design fees and unusual site conditions are extra. Confirm with contractor bids.

How the Second Story Calculator Works

Scope, size and structural work drive the cost of building up.

1. Choose Scope

A full second story, a partial build-up or a suite over the garage each carry a different base rate.

2. Size and Rooms

Enter the new floor area, finish level, and how many bedrooms and bathrooms you are adding.

3. Add Structural Work

Include items like foundation reinforcement or a new staircase for a closer, region-adjusted estimate.

Typical Cost per Square Foot by Scope

National averages from economy to premium finishes, before bedrooms, bathrooms and structural work. Your estimate is then adjusted for your state’s construction costs.

Partial Second Story $319 to $600 / sq ft
Full Second Story $298 to $560 / sq ft
Suite Over Garage $276 to $520 / sq ft

What Affects Your Second Story Cost

Structural Reinforcement

Existing foundations and walls often need reinforcement to carry a second floor, a major cost driver unique to building up.

Roof Removal and Weather

Removing the existing roof exposes the home, often requiring temporary protection and sometimes temporary housing.

Finish and Rooms

Bedrooms, bathrooms and finish level add to the base structure cost. Bathrooms are the most expensive rooms to add.

Your Region

Labor and material rates vary by state. Your ZIP code is matched to its state, and the estimate is adjusted by that state’s cost index.

Still deciding whether to build up? Our second story addition planning guide covers feasibility, living through construction and alternatives like a dormer.

Second Story Cost FAQ

How much does a second story addition cost?
A second story typically runs from about $300 to $600 per square foot depending on scope, finish level and your region, before adding bedrooms, bathrooms and structural work. Most full second stories land in the low-to-mid six figures.
Is building up cheaper than building out?
Not usually per square foot. Building up avoids new foundation and roofing over a larger footprint but adds structural reinforcement, a staircase and temporary roof removal, which raise the per-square-foot cost compared with a ground-floor addition.
Do I have to move out during construction?
Often yes for a full second story, because the roof is removed and the home is exposed. Partial additions and suites over a garage are less disruptive and may let you stay.
What structural work does a second story need?
Common items include foundation reinforcement, steel beam supports, a new staircase, temporary roof removal, HVAC extension and an electrical panel upgrade. You can add these in the calculator for a closer estimate.
Is the calculator free?
Yes. It is free and gives an instant low-to-high range plus an emailed copy of your breakdown.

Estimate Your Second Story

Get a detailed cost breakdown, then connect with vetted local contractors for real quotes.

Start the calculator